﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Web;

namespace Bing.Toolkit.Web
{
    /// <summary>
    /// 
    /// </summary>
    public class VerificationCodePage : System.Web.UI.Page
    {
        protected override void OnLoad(EventArgs e)
        {
            Page_Load(this, e);
        }
        public void Page_Load(object sender, EventArgs args)
        {
            VerificationCode code = new VerificationCode();

            string str = code.CreateVerifyCode();

            code.CreateImageOnPage(str, this.Context);

            Response.Cookies.Add(new HttpCookie("CheckCode", str));
        }
    }
    /// <summary>
    /// 
    /// </summary>
    public class VerificationCode
    {
        #region 验证码长度(默认6个验证码的长度)
        int _length = 6;
        public int Length
        {
            get { return _length; }
            set { _length = value; }
        }
        #endregion


        #region 验证码字体大小(默认为40像素)
        private int _fontSize = 40;
        /// <summary>
        /// 验证码字体大小(默认为40像素)
        /// </summary>
        public int FontSize
        {
            get { return _fontSize; }
            set { _fontSize = value; }
        }
        #endregion

        #region 边框大小(默认为2像素)
        private int _padding = 2;
        /// <summary>
        /// 边框大小(默认为2像素)
        /// </summary>
        public int Padding
        {
            get { return _padding; }
            set { _padding = value; }
        }
        #endregion

        #region 是否输出燥点(默认输出)
        private bool _chaos = true;
        /// <summary>
        /// 是否输出燥点(默认不输出)
        /// </summary>
        public bool Chaos
        {
            get { return _chaos; }
            set { _chaos = value; }
        }
        #endregion

        #region 输出燥点的颜色(默认灰色)
        private Color _chaosColor = Color.LightGray;
        /// <summary>
        /// 输出燥点的颜色(默认灰色)
        /// </summary>
        public Color ChaosColor
        {
            get { return _chaosColor; }
            set { _chaosColor = value; }
        }
        #endregion

        #region 自定义背景色(默认白色)
        private Color _backgroundColor = Color.White;
        /// <summary>
        /// 自定义背景色(默认白色)
        /// </summary>
        public Color BackgroundColor
        {
            get { return _backgroundColor; }
            set { _backgroundColor = value; }
        }
        #endregion

        #region 自定义随机字体颜色数组
        private Color[] _colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
        /// <summary>
        /// 自定义随机字体颜色数组
        /// </summary>
        public Color[] Colors
        {
            get { return _colors; }
            set { _colors = value; }
        }
        #endregion

        #region 自定义字体数组
        private string[] _fonts = { "Arial", "Georgia" };
        /// <summary>
        /// 自定义字体数组
        /// </summary>
        public string[] Fonts
        {
            get { return _fonts; }
            set { _fonts = value; }
        }
        #endregion

        #region 产生波形滤镜效果

        private const double PI = 3.1415926535897932384626433832795;
        private const double PI2 = 6.283185307179586476925286766559;

        /// <summary>
        /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
        /// </summary>
        /// <param name="srcBmp">图片路径</param>
        /// <param name="bXDir">如果扭曲则选择为True</param>
        /// <param name="dMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
        /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
        /// <returns></returns>
        public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
        {
            System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

            // 将位图背景填充为白色
            System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
            graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
            graph.Dispose();

            double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

            for (int i = 0; i < destBmp.Width; i++)
            {
                for (int j = 0; j < destBmp.Height; j++)
                {
                    double dx = 0;
                    dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
                    dx += dPhase;
                    double dy = Math.Sin(dx);

                    // 取得当前点的颜色
                    int nOldX = 0, nOldY = 0;
                    nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                    nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                    System.Drawing.Color color = srcBmp.GetPixel(i, j);
                    if (nOldX >= 0 && nOldX < destBmp.Width
                     && nOldY >= 0 && nOldY < destBmp.Height)
                    {
                        destBmp.SetPixel(nOldX, nOldY, color);
                    }
                }
            }

            return destBmp;
        }
        #endregion

        #region 生成验证码图片
        /// <summary>
        /// 生成验证码图片
        /// </summary>
        /// <param name="code">产生的验证码字符串</param>
        /// <returns>图片</returns>
        public Bitmap CreateImageCode(string code)
        {
            int fSize = FontSize;
            int fWidth = fSize + Padding;

            int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
            int imageHeight = fSize * 2 + Padding;

            System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);

            Graphics g = Graphics.FromImage(image);

            g.Clear(BackgroundColor);

            Random rand = new Random();

            //给背景添加随机生成的燥点
            if (this.Chaos)
            {

                Pen pen = new Pen(ChaosColor, 0);
                int c = Length * 10;

                for (int i = 0; i < c; i++)
                {
                    int x = rand.Next(image.Width);
                    int y = rand.Next(image.Height);

                    g.DrawRectangle(pen, x, y, 1, 1);
                }
            }

            int left = 0, top = 0, top1 = 1, top2 = 1;

            int n1 = (imageHeight - FontSize - Padding * 2);
            int n2 = n1 / 4;
            top1 = n2;
            top2 = n2 * 2;

            Font f;
            Brush b;

            int cindex, findex;

            //随机字体和颜色的验证码字符
            for (int i = 0; i < code.Length; i++)
            {
                cindex = rand.Next(Colors.Length - 1);
                findex = rand.Next(Fonts.Length - 1);

                f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
                b = new System.Drawing.SolidBrush(Colors[cindex]);

                if (i % 2 == 1)
                {
                    top = top2;
                }
                else
                {
                    top = top1;
                }

                left = i * fWidth;

                g.DrawString(code.Substring(i, 1), f, b, left, top);
            }

            //画一个边框 边框颜色为Color.Gainsboro
            g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
            g.Dispose();

            //产生波形（Add By 51aspx.com）
            image = TwistImage(image, true, 8, 4);

            return image;
        }
        #endregion

        #region 将创建好的图片输出到页面
        /// <summary>
        /// 
        /// </summary>
        /// <param name="code"></param>
        /// <param name="context"></param>
        public void CreateImageOnPage(string code, HttpContext context)
        {
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            Bitmap image = this.CreateImageCode(code);

            image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

            context.Response.ClearContent();
            context.Response.ContentType = "image/Jpeg";
            context.Response.BinaryWrite(ms.GetBuffer());

            ms.Close();
            ms = null;
            image.Dispose();
            image = null;
        }
        #endregion

        #region 生成随机字符码
        private char[] code = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

        /// <summary>
        /// 生成随机字符码
        /// </summary>
        /// <param name="len">长度</param>
        /// <returns></returns>
        public string CreateVerifyCode(int len)
        {
            StringBuilder result = new StringBuilder();

            int randValue = -1;

            Random rand = new Random(unchecked((int)DateTime.Now.Ticks));

            int arrayLength = code.Length;

            for (int i = 0; i < len; i++)
            {
                randValue = rand.Next(0, arrayLength - 1);
                result.Append(code[randValue]);
            }

            return result.ToString();
        }

        public string CreateVerifyCode()
        {
            return CreateVerifyCode(Length);
        }

        #endregion
    }
}
